Wednesday 26 March 2014

An Anniversary!

Today is the anniversary of the installation of solar panels at Montoya Mansions!

In my first year, I have generated 1636 kWh. This is comfortably more than the predicted 1400 kWh for my first year's production, and alters the payback threshhold in my favour: if the price of electricity exceeds 14.042 p per unit, my solar setup has cost less than the electricity it will generate over 25 years (accounting for deterioration).

The timing of my feed-in tariff payments has fallen nicely, such that each payment is due almost exactly halfway between an equinox and a solstice; thus, they correspond to the seasons as counted by duration of daylight. My first payment was £117.75 on 3 August; then £73.88 on 3 November. The sun could barely be bothered to rise in Winter, leading to a dire £29.12 on 3 February (although it still more than covered the £1.82 per week standing charge). Come 3 May, I expect to receive another £70 or 80 for the Spring (this payment and the Autumn one should be fairly similar, by symmetry: the graph of day length vs. day of the year is sinusoidal).

When I get my storage batteries and UPS plumbed in, I should be able to save even more, as I won't need to pay for all the electricity I will be using in the evening .....

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